PMSF stands for Phenylmethylsulfonyl fluoride. It is used as an inhibitor of protease activity for example in protein purifications or coimunoprecipitations.
Molecular W.: 174.19
Don't try solution in water, it does not work. Take ethanol or methanol. 200 mM stock solution are stable for months at 4°C. A normal endconcentration of PMSF is probably about 1mM of course depending on the experimental setup.
PMSF is poisenes and should be handeld carefully.